A new paper authored by archeologists with Seoul National University has suggested that the Sahara Desert, once green and wet, dried out as a result of the actions of ancient peoples. The spread of agriculture depleted the Sahara’s plant life and caused the region’s the shift to a desert biome, the paper claims.
Very interesting research, with some implications for what's going on in the Arctic now.
"The underlying causes of this drying and desertification has previously been attributed to subtle changes in the Earth’s orbit, which in turn influenced atmospheric weather patterns and led to a reduction of the amount of rainfall in northern Africa. But Wright, whose scientific research has led him to exploring Neolithic-age archaeological sites all over the world, suggests that this is not the full picture. “In East Asia there are long established theories of how Neolithic populations changed the landscape so profoundly that monsoons stopped penetrating so far inland”, explains Wright, also noting in his paper that evidence of human-driven ecological and climatic change has been documented in Europe, North America and New Zealand. Wright believed that similar scenarios could also apply to the Sahara."
https://blog.frontiersin.org/2017/03/14/did-humans-create-the-sahara-desert/Full paper:
http://journal.frontiersin.org/article/10.3389/feart.2017.00004/full